Harvest - Simple time tracking, fast online invoicing, and powerful reporting software. Simplify employee timesheets and billing. Get started for free.
InvoicePlane - Free and open source invoicing application to host on your own server.
Invoice Ninja - Invoice Ninja is a free, open-source solution for invoicing and billing customers.
WatchMe - Flamebrain Technologies – Home of WatchMe – Where does the time go?
Crater - Free Open-Source Invoice app for freelancers & small businesses.
timeBuzzer - timeBuzzer enables freelancers and project-driven teams to track their time at the touch of a button, understand where their time goes and create reports with just a few clicks.